Introdouction:Tooth eruption is recognized as an important aspect of human growth and development. It can be influenced by a number of factors, and it may reflect the general development of a child’s body. The purpose of this study was to determine the age at which the first primary tooth erupted and its relationship with height, weight and head circumference in 3-15-month children in the city of Rasht,Iran.Materials and methods: This descriptive, cross-sectional study was conducted on 648 children (288 girls and 360 boys) aged between 3–15 months, which were randomly selected from all health care centers in Rasht (the children visit these centers regularly for vaccinations). Height, weight, and head circumference were measured on the same day. From the obtained data, descriptive statistical indices were calculated for the eruption time of the primary central incisors. Cox regression analysis was used to determine the relationship between tooth eruption and the three growth parameters.

Results: The timing of the eruption of the first primary tooth ranged from 5 to 14 months. The first erupted tooth was the mandibular central incisor, with the mean age of eruption of 9.93 ± 0.11 months in girls and 10.13 ± 0.1 months in boys. There was a significant association between the eruption time of the first primary tooth and weight-for-age in both girls and boys. The relationships of first primary tooth eruption with head circumference-for-age and height-for-age were significant only in boys.

Conclusion: The first primary tooth erupted earlier in girls than in boys, and primary tooth eruption was significantly related to the measured growth parameters, i.e., height, weight, and head circumference.